I mostly agree with the statement, "unanswerable questions cannot be solved with reason." Unanswerable questions are unanswerable because they lack some quantifiable aspect. A fundamental truth can only be assumed, upon which reason then builds. But there are many such possible truths.

I would say that reason alone is insufficient at answering most questions, if we are interested in the facts. The ultimate nature of being is subject only to speculation, in which reason plays an important part in revealing possibilities.

You wrote: "A fundamental truth can only be assumed, upon which reason then builds." This seems significant -- does it have any relation to A priori and A posteriori? It seems a little bit different.

Then you write: "The ultimate nature of being is subject only to speculation, in which reason plays an important part in revealing possibilities."

But what if you were to shorten your sentence: "The ultimate nature of being is subjective." ?

I'm all for reason of course. I just feel that at some point it becomes a limitation -- an important limitation for producing materialization according to a specific language -- but otherwise a limitation, and a barrier that prevents knowing. Reason must allow for ultimate uncertainty, and nothing can ever be truly known.